1. Field of Art
The invention relates to stands used to hold chemical containment tanks of chemicals over a spill tub, as well as associated screens used to provide ecological protections and to provide human access to the tanks.
2. Discussion of the Background Art
The western U.S. and Alaska are crisscrossed with oil and other pipelines. To facilitate the flow of gas or oil through these pipelines, or to facilitate gas or oil extraction from well heads, pipeline owners place tanks of chemicals alongside of the pipelines or well heads. In natural gas extraction and transport, methanol is added at or near the well head take the moisture out of gas coming out of the ground so the moisture will not corrode the pipe line. In oil extraction, other chemicals, such as drag reducers, may be added.
Because many natural gas well heads are unmanned for much of the time, self-operating chemical injection hardware is positioned near the well head or along the pipeline. Accompanying this equipment are large barrels of chemicals that are to be injected into the well head or pipeline. The chemicals are drawn from the containment tanks via a solar powered pump or other pumping infrastructure. The chemical containment tanks are initially and then periodically filled from a truck having a large reservoir of chemicals. In natural gas sites, a truck will fill the chemical containment tanks to full or nearly full capacity (e.g., 100s of gallons).
Environmental regulations require that most if not all chemicals injected into natural gas and oil well heads and pipelines be prevented from entering the local watershed. Thus, regulations also require oil pipeline owners and operators to remove any contaminated soil that may result from a leak. The procedures to remove contaminated soil are expensive and time-consuming. Also, leaks may result in fines and/or disruptions to operations to facilitate clean up. To avoid these costs, oil and gas companies have begun to place barriers between the chemical barrels and the ground (e.g., spill tubs under the chemical containment tanks) to catch any chemicals that leak during filling or operation. However, environmental regulations also require that wildlife (e.g., birds, mammals, etc.) be prevented from accessing or coming into contact with any chemicals that may spill into the lower spill tubs. In some cases, insects are attracted to any spilled chemicals. Birds, reptiles or small mammals then eat the insects and die from poisoning. In other cases, wildlife dies after drinking rainwater captured in the open spill tubs that may be polluted with chemical spillage. Fines assessed to well owners may vary with the species of animal that is killed due to exposure to the chemicals (e.g., fines for a poisoned eagle may be higher than for other birds).
Thus, oil pipeline owners and operators have a need for chemical spill prevention/mitigation techniques and tools so as to avoid any chemicals from the chemical containment tanks from reaching the ground or the watershed, and to prevent birds and other animals from coming into contact with any chemicals that may be spilled into a corresponding spill tub.
One approach to this need has been to place large metal or poly containment tanks of chemicals in open-topped metal or poly spill tubs. Electro-mechanical equipment used for pumping the chemicals may be installed inside or outside chemical containment tank or the spill tubs. However, these tanks and tubs corrode when exposed to the elements. Furthermore, static electricity can form in or on metal components of the tanks and tubs, leading to further corrosion or to damage to electronic equipment (e.g., pumps) associated with the chemical injection. Furthermore, access to any electronic equipment inside the metal or poly spill tubs, and filling or moving the barrels of chemicals, is difficult to manage.
Thus, as recognized by the present inventor, there is a need for an improved device and technique to avoid any containment from the containment tanks or spill tubs onto the ground or into the watershed, as well as improved protection of wildlife and improved filling and maintenance of the chemical containment tanks, spill tubs and associated equipment.